Rotary electrical switch



June 7 1949 E. H. REllNscHMlD-r, JR 2,472,230

l Ronny ELECTRICAL swl'rcn Filed March 12, 1948y 2 Shae'esSle'ec- 1 A l lll/ l-'e Ugg!! A i' n Zhwmtof EWARD il Rf/MSCHN/DT June 7, 1949. E. H. RElNscHMlDT, JR 2,472,230

' ROTARY ELECTRICAL swITcH 2V shee'ts-sheet 2 Filed March 12, 1948 FIG. 6.

Y lvEN-roR Y EUA/ARO /z Rf/NSc/fM/or 'avw' l n? Patented June 7, 1949 Edward H. Reinschmidt, Jr.,-Cedar.-Rapids, Iowa, assigner -to Collins Radio4 Company, .Cedar Rapids, Iowa, .a corporation .of Iowa AApplication March 112, 1948,- Serial No. 14,557

6-Claims.` .(Cl. 2.0.0-158) This invention `:relat s @to .\,electrical.switches and more `particularlyito:switches having `a multiplicity of stationary econtacts..

A principal object .of the invention is to .pro. Videla rotary switchthaving falseries .of fixed .or

bank contacts arranged in a plural-turn helical.

path, and .a ,cooperatingaotary brush .or wiper whichis .arranged :to followal corresponding helical path.

Another object Eis :to provide'a multi-point se-v lector switch wherein :thestationary or banks contacts are 'mounted Y'andixtend interiorly of .a dust-proof casing; .andra rotary brush or wiper. is carriedby a shaft `extending axially through.

the casing. As aresultfoiathisconstruction, .it ispossible to .provide Vthe switch-with any desired number of contacts arranged -inV a plural-turn helix While protecting-both the fxed `.and rotary 1 contacts .from contamination by dust,V moisture and the'like.

A feature of the invention :relates to a switch construction in -the1formvof a cylindrical yenclos- Y ing housing :havinga multiplicity .of stationary contacts extendingthrough fthe housing wall and .arrangediina plural-turnzhelical path. A rotary wiper cbrush-'is mounted -onra ,shaft `extending centrally .through the :housingand this brush is carried .by sa :member whichlis :subjected` to a .combined rotar-.y and` rectilinearmotion` as the 4shaft is yturned'so as 'Ito .cause the -awiper brush successively :to engage/each: of the sta-4 tionary A contacts in `the-severa1 --successive helical turns as the said Ishaft is continuously rotated., Another feature-of the invention relates fltothe novel organization,arrangement and'relative locationof parts which-cooperate 1to 'provide an improved multi-:turn selector 'switch 'of the dustproof'type.

Other features and" advantages V'not particularly enumerated williberapparent after a con-` sideration of the-followingfdetailed "descriptions andthe appendedclaims.

In the drawing whichshows onepreferred em'- bodiment,

Fig. 1 is a plan view of a, switch according 'to' the invention.

Fig. 2 is'a'sectional'view of Fig.l 1,' taken along theline 2-2 thereof.

Fig.'3 is a sectional viewof Fig. 2,"takenalon'g the line 3-3 thereof,

Fig. 4 is a sectional view .of Fig.'2, .taken along the line 'II-4 fthereof;

Fig.v 5 is a detail'viewi'ofthe rotor'unit ofthe switch.

Fig. 1.6 is alongitudinal sectional viewl of amodication of the invention.

Fig 'l is asectional view vof Fig. 6 taken along.A

the line 1 -'I thereof.

Fig. 8 fis '.a detail view of :the rotorvof Fgs..6.

and 4'7.

The switch-.comprises `a cylindrical .enclosing casing I of suitable :insulating material such as a molded .phenolic material having its right.-

hand end formed with an integral lug or knob l.2 Y. which is .adapted .to t within a corresponding. opening lin a suitable rxed support or panel y3.A

to which the switch is tobefastened, in order -.to

prevent the casing from turning as the switch;`

rotoris turned. The .casing I has one -end closed by anintegral .wall 24, having a ,central opening:

into rwhich is molded .a metal bushing 5 which has .its external periphery :6 -threaded to `receive a suitable fastening nut I for mounting the` switch on the panel .3. The opposite end .of casing-.I has seated therein a closure member 8 which ymay be of the :samematerial as the cas-` ing I, and maybe .fastened vthereto in anyconvenient manner, :for example by cement or by set screws. Themember l8 has a central `open-- ing in which is molded ametalbearing sleeve 9 to receivethe reduced circular end of the rotary shaft .IIJ. Fastenedto the .inner face of member B by suitable eyelets or rivets II, is a metal disc. I 2, which is provided with an integral lug 1.3.

extending through the member 8. For v-the .purpose .of restraining-the yshaft I0 against lengthwise movement with respect to ,thecasing it provided with acircular groove-I4, into which.

is fitted a lretainerring I6. The left-,handend of shaft I0 has aat which .registers with a corresponding opening in .an insulating disc .0r-

wafer I8. .Attached to the disc I8 by suitable eyelets or rivets .I9 Vis .a metal disc 20, having.

three .offset-spring Alugs 22| which wipe against the above-describedmetal disc I2 as the shaft .I0 is rotated.

The portion 22 ofthe shaft IIl ,is circularin peripheryV so as to-.provide asmooth bearing surface within .thebushing 5. However, the .re-

mainder .of the length Aof .shaft I0 .has flatsl, 2'4,..and registering with .these ats adjacent the. wall Vmember Y4.and stakedto shaft I0, vthereis a.

metal member 25 carrying diametrically opposite spring. arms 29, the memberf25 having respective. openings in whichfare-seated'the detent balls.'26,`.

2'I. The ballsl 6,.' 21, cooperate with` correspond.-V ing embossed .notches..28, .integrally molded .on

the .inner .face .of .member .4. Also fitted .on .to.

theshaft IU isa .rotor member 30 of.siJ.ita .l: le`

on roto-r 3D. The left-hand face of rotor 34 has a well 3| to receive the coil 32 when it is collapsed as the rotor is moved to the left.

The longitudinal sliding or feeding movement of the rotor 3i) is effected by engagement with the successive stationary conta-cts 34, which are Y mounted in the casing I. Preferably, the internal periphery of casing I is provided with a continuous helical groove and this groove is provided with a series of equally-spaced rectangular openings into which are tted the several contact vmembers 34. As shown more clearly in Fig. 3, each of these stationary contacts is in the form of a suitable spring metal such as beryllium copper having a central main Contact portion 36, which extends through the corresponding rectangular opening in the casing I. Each contact member is also provided with a pair of integral lateral lugs 31, 38, terminating in respective hooked chamfered portions 39, 44, which resiliently lock with the edges of the corresponding openings in casing I. Thus, ea-ch of the stationary contacts is firmly anchored in the casing I and it has its inner contacting end extending interiorly of the casing a suificient distance to be engaged by the rotary brush or wiper 4I' which is carried by the rotor 30. The openings in the casing l through which the contact members 34 pass, provide a tight fit with respect thereto, so as to protect the interior of the casing from the ingress of dust, moisture and the like.

The longitudinal feeding movement of the rotor 3B is effected by means of a continuous helical slot 42 which is formed in the outer periphery of the rotor 30, the pitch of this helical slot being the same as the pitch of the helical groove 35, and therefore the same as the pitch of the path along which the various stationary contacts 34 are located. Preferably, the wiper brush 4I is attached to the rotor 3U by a suitable eyelet or rivet 43, so that the said brush is recessed below the outer peripheral surface of the rotor. However, the rotor 30 has an outer diams eter which is only slightly less than the inner diameter of the casing I, so that the helical groove 42 is at all times in registry with a series of stationary contacts 34. Consequently, as the shaft IE! is turned, it causes the wiper 4i to engage the stationary contacts 34 successively, and

by reason of the helical grooved engagement between the periphery of the rotor and the corresponding helically mounted stationary contacts 34, the said contacts 34 act in the nature of a lead screw, causing the rotor 30 to be advanced along the length of shaft Il] as the latter is being turned. The axial feeding movement of the rotor is limited by the end rings I1 and 44 fitted into the corresponding grooves on shaft Ill. In order to complete the electrical circuit between wiper 4I and lug I3, the spring 32 can be connected at its right-hand end to the eyelet 43 in any suitable manner, for example by soldering.

Referring to Figs. 6 and 7, there is shown a modification of the switch of Figs. l to 5. In general, this modied structure is the same as that of Figs. l to 5, except that the common return contact members I2 and 20 at the end of the switch are deleted and are replaced by a single continuous plural-turn helical metal rib 45 which is fitted within a coresponding pluralturn helical recess on the inner periphery of the casing I'. Preferably, the rib 45 extends inwardly into the casing to the same distance as the inwardly projecting ends of the stationary contacts 34. The identical structural elements of the embodiments of Figs. 1 to 5 and Figs. 6 and 7 are designated alike. In the embodiment of Figs.

6 and '7, the rotor 30 instead of having a single helical groove 42, has a pair of parallel helical grooves 42, 46 (Fig. 8). The groove 42 receives and cooperates with the inwardly projecting ends of the stationary 4contacts 34 as hereinabove described, while the groove 46 receives and cooperates with the inwardly projecting end of the rib 45. The rotor 30 carries in addition to the foregoing-described wiper 4I, an additional wiper 41, both of which are electrically interconnected by the common fastening eyelet 43. The wiper 4l therefore continuously engages the common return rib 45, while the wiper 4I engages the stationary contacts successively, as the shaft Ill is rotated.

While the drawing shows a rotor carrying a single wiper 4I cooperating with the stationary contacts 34, it will be understood, of course, that this rotor may carry more than one such wiper. Likewise, while the wiper 4l has a peripheral width which is less than the peripheral spacing between successive stationary contacts 34, it will be understood that if this wiper is to be of the shorting type, it may be made of a sufficient peripheral width so that it can engage two or more stationary contacts for each position of the shaft l0. Preferably however, the shorting action is achieved by using contacts 34 having wider contact surfaces so that adjacent contacts can be bridged by the wiper. It will be understood, of course, that the number of stationary contacts may be increased by either decreasing their circumferential spacing or by increasing the number of helical groovesV and in which the additional stationary -contacts are mounted, and by likewise employing a corresponding change in the size of the detent balls 26 and their associated centering bosses 28. Furthermore, if desired, the left-hand end of shaft Ill can protrude through the casing so that it may be appropriately coupled to the rotary shaft of a similar switch unit, thus permitting two or more of such units to be operated in tandem from a single knob or dial attached to shaft Il). Instead of stacking separate complete units together in end-on relation to increase the number of circuit controls, the casing I may be made in separate cylindrical sections which can be keyed or fastened together to form a single complete casing, depending upon the number of stationary contacts that are to be employed, and likewise the shaft IIl can be made in separate attachable sections to be keyed together to provide the extended guiding means for the rotor 3U.

While certain particular embodiments have been described herein, it will be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

l. An electricl switch comprising a cylindrical casing, a plurality of circumferentially-spaced stationary contacts carried by said casing arranged in a helical path therearound and extending inwardly thereof, a rotor drum of insulation concentrically mounted with relation to said stationary contacts interiorly of said casing, said rotor drum having a diameter approximating the internal diameter of said casing and carrying at least one wiper brush for engaging said stationary contacts as the rotor is rotated, and a single turn helical groove on the external periphery of said rotor and engaging with said contacts for subjecting said rotor to an axial feeding movement as said rotor is being rotated.

2. An electric switch, comprising a cylindrical casing, a plurality of circumferentially-spaced stationary contacts mounted in said casing along a plural turn helical path, a rotatable shaft concentrically mounted within said casing, -a rotor member slidably mounted on said shaft but rotatable as a unit therewith and having a single but continuous peripheral helical groove, at least one Wiper brush carried by said rotor member and successively engaging said stationary contacts as the rotor is rotated, said stationary contacts and said rotor groove engaging each other to impart a lead screw feed motion to the rotor as it is being rotated.

3. An electric switch, comprising a cylindrical casing, -a continuous rib on the inner periphery of said casing in the form of a plural turn helix, a plurality of stationary contacts mounted in said casing and located in the path of a plural turn helix with the inner ends of the contacts extending radially inward of the casing, a rotatable shaft passing centrally through said casing, a rotor carried by said shaft for sliding movement thereon and for rotation as a unit therewith, said rotor carrying a pair of wiper brushes one of which engages said helical rib and the other of which engages said stationary contacts as the said shaft is rotated said rotor having means to advance said wipers axially of said shaft as it is being rotated.

4. An electric switch according to claim 3, in which said rotor has a pair of parallel helical grooves on its periphery having the same pitch as said helical rib, one of said grooves receiving and cooperating with the stationary contacts and the other groove receiving and cooperating with said stationary rib to effect said axial movement of the rotor as said shaft is rotated.

5. An electric switch comprising, a.cylindrical casing, a plurality of stationary contacts anchored in said casing along a plural turn helical path each contact having a portion extending radi-ally inward of the casing, a shaft rotatably mounted in the end walls of the casing, a rotor member slidably mounted on said shaft but rotatable as a unit therewith, at least one wiper brush carried by said rotor, means normally biassing said rotor towards one end of the casing, and means responsive to the rotation of said shaft to cause said rotor to undergo a combined rotary motion and axial feed motion whereby said Wiper successively engages said stationary contacts, one end wall of the casing carrying a fixed contact plate which eng-ages a rotary contact member mounted on said shaft, and the said means for normally biassing the rotor towards one end of the casing comprises a spring which at one end is in electrical engagement with said rotary contact member and at the opposite end with said wiper.

6. An electric switch comprising, a cylindrical casing, a plurality of stationary contacts anchored in said casing along a plural turn helical path each Contact having a portion extending radially inward of the casing, a shaft rotatably mounted in the end Walls of the casing, a rotor member slidably mounted on said shaft but rotatable as a unit therewith, at least one wiper brush carried by said rotor, means normally biassing said rotor towards one end of the casing, and means responsive to the rotation of said shaft to cause said rotor to undergo a combined rotary motion and axial feed motion whereby said wiper successively engages said stationary contacts, said rotor having a peripheral helical groove of the same pitch as said helical path, and said wiper is mounted in said rotor and in communication with said groove so as to be below the external periphery of said rotor but engageable with said stationary contacts as the rotor is turned.

EDWARD H. REINSCHMIDT, J R.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,538,535 Welling May 19, 1925 1,606,153 Douglas Nov. 9, 1926 1,881,622 Janson et al Oct. 11, 1932 2,172,218 Mylius Sept. 5, 1939 2,279,107 Cahn Apr. 7, 1'942 

